r744 mac status and system standardisation · 13 mpa acc.to sae j 639 standstill system pressure...
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R744 MAC Status and System Standardisation
Stefan MorgensternVDA-Wintermeeting, Saalfelden (A), 13.02.2008
Page 2VDA Wintermeeting, 13.02.2008
R744 MAC Status and System Standardisation AK dt. OEM 2.4.2a
Introduction
Performance
Risks
Conclusion
Present and Ongoing Activities
Standardisation
Page 3VDA Wintermeeting, 13.02.2008
R744 MAC Status and System Standardisation AK dt. OEM 2.4.2a
Performance
Risks
Conclusion
Present and Ongoing Activities
Standardisation
Introduction
Page 4VDA Wintermeeting, 13.02.2008
R744 MAC Status and System Standardisation AK dt. OEM 2.4.2a
VDA press release, 06-09-2007
… Following investigation of numerous alternatives to the refrigerant currently being used, vehicle manufacturers in the German Association of the Automotive Industry (VDA) have now agreed to use the especially environmentally-friendly natural refrigerant R744 (carbon dioxide) in vehicle air-conditioning systems in future – and they will be the first world-wide automotive companies to do so. …
VDA Statement on Alternative Refrigerants
Page 5VDA Wintermeeting, 13.02.2008
R744 MAC Status and System Standardisation AK dt. OEM 2.4.2a
compared to R134a systems R744 MAC …
�reduce direct greenhouse effect by a factor of more than 1000
�offer improved AC Performance at equal package space
�show higher over all efficiency
�heat pump function as future option
furthermore …
�human’s exposure to R744 is scientifically well researched
�R744 is non flammable
�R744 follows all present and future legal demands
F-Gas-Directive:“With effect from 1 January 2011 Member States shall no longer grant EC type-approval or national type-approval for a type of vehicle fitted with an air conditioning system designed to contain fluorinated greenhouse gases with a global warming potential higher than 150.”
Why R744?
Page 6VDA Wintermeeting, 13.02.2008
R744 MAC Status and System Standardisation AK dt. OEM 2.4.2a
Introduction
Performance
Risks
Conclusion
Present and Ongoing Activities
Standardisation
Page 7VDA Wintermeeting, 13.02.2008
R744 MAC Status and System Standardisation AK dt. OEM 2.4.2a
BMW Group Standard Cool Down@ 40°C / 30%r.F. / 1000 W/m² solar load, 90 min soak
R744
R134a
“Plug and play" Cool Down Performance at series conditions w/o optimising measures
Head
Vents
Page 8VDA Wintermeeting, 13.02.2008
R744 MAC Status and System Standardisation AK dt. OEM 2.4.2a
Temperature distribution consideration for fuel consumption estimation
Data from National Climatic Data CenterU.S. Department of Commerce; www.ncdc.noaa.gov8000 weather stations worldwideData considered from the years 2000 to 2006
intersection at ca. 35°C
frequency of vehicle use vs. ambient temperature
Page 9VDA Wintermeeting, 13.02.2008
R744 MAC Status and System Standardisation AK dt. OEM 2.4.2a
relative comparison of A/C caused fuel consumption
100 92
0
10
20
30
40
50
60
70
80
90
100
Del
ta F
uel C
onsu
mpt
ion
[%]
R134a R744
100 91
0
10
20
30
40
50
60
70
80
90
100
Del
ta F
uel C
onsu
mpt
ion
[%]
R134a R744
10088 89
0
10
20
30
40
50
60
70
80
90
100
Del
ta F
uel C
onsu
mp
tion
[%]
R134a 2005 R744 2005 R134a 2007*
*Improved System with integrated IHX
10088
0
10
20
30
40
50
60
70
80
90
100
Del
ta F
uel C
onsu
mpt
ion
[%]
R134a R744
vehicle A vehicle B
NEDC (warm start)28 °C, 40 % r.h.40 % Evap. Air Mass flow, OS-AirEvaporator Setting 5°C
NEDC (warm start)28 °C, 40 % r.h.40 % Evap. Air Mass flow, OS-AirEvaporator Setting 5°C
vehicle C vehicle D
Page 10VDA Wintermeeting, 13.02.2008
R744 MAC Status and System Standardisation AK dt. OEM 2.4.2a
with R744 MAC …
�no secondary loop is necessary, direct evaporating system
�no fire mitigation system needed
�fits to R134a vehicle architecture
�fits to R134a vehicle package
Vehicle Integration
Page 11VDA Wintermeeting, 13.02.2008
R744 MAC Status and System Standardisation AK dt. OEM 2.4.2a
Introduction
Performance
Risks
Conclusion
Present and Ongoing Activities
Standardisation
Page 12VDA Wintermeeting, 13.02.2008
R744 MAC Status and System Standardisation AK dt. OEM 2.4.2a
Costs:
�high pressure levels, permeation demands
�additional parts, more complex parts
�additional refrigerant type (quantity split, parallel handling, parallel engineering)
Maturity and Quality:
Development:
�no long term experience, no wide base experience
Production:
�no mass production experience
Risks
Page 13VDA Wintermeeting, 13.02.2008
R744 MAC Status and System Standardisation AK dt. OEM 2.4.2a
Solving Cost and Quality Issues by
�System Standardisation
�Component Standardisation
Risks
Evaporator
Gas Cooler
Accumulator
& IHX
DPOT
Compressor
12
MPa
16
MPa
P/TT
T
Evaporator
Gas Cooler
Accumulator
& IHX
DPOT
Compressor
12
MPa
16
MPa
P/TT
T
Evaporator
Gas Cooler
Accumulator
& IHX
DPOT
Compressor
12
MPa
16
MPa
P/TT
T
Evaporator
Gas Cooler
Accumulator
& IHX
DPOT
Compressor
12
MPa
16
MPa
P/TT
T
OEM A OEM B OEM C OEM D
OEM A OEM B OEM C OEM D
Page 14VDA Wintermeeting, 13.02.2008
R744 MAC Status and System Standardisation AK dt. OEM 2.4.2a
Introduction
Performance
Risks
Conclusion
Present and Ongoing Activities
Standardisation
Page 15VDA Wintermeeting, 13.02.2008
R744 MAC Status and System Standardisation AK dt. OEM 2.4.2a
System Standardisation
2
4
6
8
10
12
14
16
18
20
50 150 250 350 450 550spec. Enthalpie h [kJ/kg]
Ref
riger
ant p
ress
ure
[MP
a]
140°C20°C 40°C 80°C60°C 160°C120°C100°C
Maximal burst pressure
Minimal Burst pressure
+1MPa
-1MPa
Mean Burst Pressure 16 MPa
Max allowable pressure16 MPa
Tolerance
Max operating pressure 14 MPa Max. working
pressure 13,.3 MPa
Max. release pressure17 MPa accord. SAE J639
Max operating temperature 165°Cshort time 180°C
less 5'
Min operating pressure 2,5 MPa
Working Pressure and Temperature Limits
Page 16VDA Wintermeeting, 13.02.2008
R744 MAC Status and System Standardisation AK dt. OEM 2.4.2a
System Standardisation
2
4
6
8
10
12
14
16
18
20
50 150 250 350 450 550
spec. Enthalpie h [kJ/kg]
Ref
iger
ant p
ress
ure
[MP
a]
140°C20°C 54°C40°C 80°C60°C 160°C120°C100°C
System charged
with s/c: 260 g/l
J 639 Soak-Temperature
Max burst/relief pressure
Min burst/relief pressure
+1 MPa
-1 MPa
Mean Burst Pressure 12 MPa
Max allowable pressure 12 MPa
Tolerance
350 gr/ l
200 gr/ l
260 gr/ l
225 gr/ l
400 gr/ l
Max release pressure13 MPa acc.to SAE J 639
Standstill System Pressure Limits
Page 17VDA Wintermeeting, 13.02.2008
R744 MAC Status and System Standardisation AK dt. OEM 2.4.2a
Component Standardisation
drying agentØ = 50 mm h = 380 mm, Ø = 75 mm h = 170 mm,coaxial pipe, dia = 16 mm
Accumulator and Internal Heat exchanger
HP LT elastomer hose under qualification
LP elastomer hose HP HT corrugated tubes
Flexible piping
ID Tube from stainless Steel are under discussion (6 mm)
Aluminium tube with inner Ø 9/6/4 mmSS Tubes at flexible hoses Mat.1.4541
Piping
Needs to fit into R134a evaporator package
Safe Evaporator; Depth ≤ 40mmEvaporator
No heat transfer from IHX in liquid refrigerant, Vapor quality (X) indep. from refrig. flow, drying agent
Ø = 75 mm h = 380 mm, Ø = 85 mm h = 170 mm
Accu/IHX-Unit
P/T Sensor and HP Service under investigation
PF or CF- Design Depth ≤ 16mmGas cooler
Mass flow as f(control current), 400 Hz PWM variable
Externally controlled s/m/lstroke Volume, proportional control valve
Compressor
Remark Description / characteristicComponent
Page 18VDA Wintermeeting, 13.02.2008
R744 MAC Status and System Standardisation AK dt. OEM 2.4.2a
Component Standardisation
HP and LPHigh pressure relieve devices
CO2 with odorantRefrigerant
For workshop useService equipment
Evaluation in Prod. & ServiceBlock Joint technology Joints
’Push Pin’ Principle Charge & Service Port
For plant use and rework incl. leak detection support
Production and plant service units
TXVOTB
Expansion Device
-Sealing principle in revision, LIN connection in discussion,
Integrated Unit: Thermocouple at top, both LIN Bus Communication and analogue communication
P/T Sensor
Remark Description / characteristicComponent
Page 19VDA Wintermeeting, 13.02.2008
R744 MAC Status and System Standardisation AK dt. OEM 2.4.2a
Introduction
Performance
Risks
Conclusion
Present and Ongoing Activities
Standardisation
Page 20VDA Wintermeeting, 13.02.2008
R744 MAC Status and System Standardisation AK dt. OEM 2.4.2a
Engineering:
�developing and defining target R744 system
�optimising cost, acoustics, weight, variants, …
Production:
�investigation about influence on production site and processes
�variant handling, leak testing and charging within the existing plant and production, assembly, …
Service:
�service equipment and process, unmounting/mounting
Present and ongoing OEM activities
Page 21VDA Wintermeeting, 13.02.2008
R744 MAC Status and System Standardisation AK dt. OEM 2.4.2a
Introduction
Performance
Risks
Conclusion
Present and Ongoing Activities
Standardisation
Page 22VDA Wintermeeting, 13.02.2008
R744 MAC Status and System Standardisation AK dt. OEM 2.4.2a
major steps
�concept confirmation
�precise detailing and confirmation of target vehicle demands (project)
�development for series quality, process confirmation
�SOP
Conclusion
Page 23VDA Wintermeeting, 13.02.2008
R744 MAC Status and System Standardisation AK dt. OEM 2.4.2a
�R744 MAC is the right decision and the only known alternative refrigerant to meet 2011 SOP
�we made a good approach to assess alternatives
�the refrigerant type should not be a selling proposition
�everyone’s invited to cooperate
Conclusion